ARTICLE XVII
RITES AND CEREMONIES
SECTION 1.
TEXTS; COLLECTIONS; EXTRACTS. -- The texts used in the
Mass, Liturgy and administration of the Sacraments (Missale
Romanum, Pontificale, Breviarium) shall conform to the Typical
Editions issued by the Holy See prior to 1964. Ritual
collections and extracts may be used only insofar as these agree
with the appropriate typical edition.

SECTION 2.
LANGUAGE. -- The Mass, Sacraments, Office and other
ceremonies may be conducted either in the Latin Language or in
the vernacular, as pastoral requirements dictate and according to
local custom, but in all cases such linguistic renderings shall
be uttered with precision. The use of the Latin Canon in Masses
offered in the vernacular, as well as the use of Latin for the
essential form of the administration of the Sacraments, may be
determined as appropriate by local authority.

Pope Saint Pius V, Quo Primum Tempore, July 14, 1570

.... So that the rite of the Holy Roman Church, the mother
and teacher of all churches, may be adopted and observed
everywhere, henceforth perpetually, in all future times,
throughout the provinces of the Christian world; in
Patriarchates, Cathedrals, Colleges, and Parishes, whether
secular or those of religious orders; in monasteries, whether of
men or of women, as well as in the military orders, even in
churches and chapels without the cure of souls; when High Mass is
sung aloud with a choir, or in Masses merely recited; those who
by custom or law celebrate in accordance with the rites and
customs of the Roman Church are to make use of this Missal edited
by Us for the chanting and reading of Mass....

.... Furthermore, by these presents, in virtue of Our
Apostolic Authority, We concede and grant, in perpetuity, that
for the chanting or reading of Mass in whatever church, this
Missal may be followed absolutely, without scruple of conscience,
or fear of any other penalty, sentence, or censure, and may be
used freely and lawfully. Nor are Superiors, Administrators,
Canons, Chaplains, and other secular priests, or religious by
whatever order or title designated, obliged to celebrate Mass
otherwise than ordered by Us. We likewise order and declare that
no one is to be forced or coerced to alter this Missal, and that
this present document can never be revoked or modified but always
will remain valid and in full force. Previous constitutions and
decrees of the Holy See, general and special constitutions and
edicts of provincial or synodal councils, the practice and custom
of the aforementioned churches, established by long and
immemorial prescription -- saving only usages over two hundred
years -- to the contrary notwithstanding....

Council of Trent, "Canons on the Sacrifice of the Mass," 17 September 1562:

Canon 3. If anyone says that the Sacrifice of the Mass is
one only of praise and thanksgiving; or that it is a mere
commemoration of the sacrifice consummated on the cross but not a
propitiatory one; or that it profits him only who receives, and
ought not to be offered for the living and the dead, for sins,
punishments, satisfactions, and other necessities, let him be
anathema.

Canon 9. If anyone says that the rite of the Roman Church,
according to which a part of the canon and the words of
consecration are pronounced in a low tone, is to be condemned; or
that the Mass ought to be celebrated in the vernacular tongue
only ... let him be anathema.

The Roman Catechism, 1566, Pt. II, Ch 4., No. 24.

The additional words, "for you and for many -- pro vobis et pro multis"... serve to declare the fruit and the advantage of His passion, for if we look to its value we must confess that the Redeemer shed His blood for the salvation of all; but if we look to the fruit which mankind have received from it, we shall easily find that it pertains not to all, but to many of the human race.... When He added, 'and for many,' He wished to be understood to mean the remainder of the elect from among the Jews or Gentiles.

With reason, therefore, were the words 'for all' not used,
as in this place the fruits of the Passion are alone spoken of,
and to the elect only did His Passion bring the fruit of
salvation. And this is the purport of the Apostle (Hebrews ix:
28) when he says: 'Christ was offered once to exhaust the sins of
many'; and also of the words of our Lord in John: "I pray for
them; I pray not for the world, but for them whom Thou hast given
Me, because they are Thine."

"This is the chalice of My blood, of the New and Eternal Testament,
the Mystery of Faith, which shall be shed for you and for many unto the
forgiveness of sins."

Christ's passion sufficed for all; while as to its efficacy it
was profitable for many....

Some have maintained that the words "This is the chalice of My
blood" alone belong to the substance of this form, but not those words
which follow. Now this seems incorrect, because the words which follow
them are determinations of the predicate, that is, of Christ's blood;
consequently they belong to the integrity of the expression.

These words are pronounced in the person of Christ, Who says of
Himself (John xiv: 6): _I am the truth._

I answer that, There have been many opinions on this point. Some
have said that in the expression, "This is My body," the word "this"
implies demonstration as conceived and not as exercised, because the
whole phrase is taken materially, since it is uttered by a way of
narration: for the priest relates that Christ said: "This is My body."

But such a view cannot hold good, because then these words would
not be applied to the corporeal matter present, and consequently the
sacrament would not be valid....

Pope John XXIII, Missale Romanum, 1962
"On the Defects Which May Occur in the Celebration of Mass"

V - Defects of the form
Defects on the part of the form may arise if anything is missing
from the integrity of the words required for the act of consecrating. Now
the words of the Consecration, which are the form of this Sacrament, are:
"For this is My body," and "This is the chalice of My blood, of the New
and Eternal Testament, the Mystery of Faith, which shall be shed for you
and for many unto the forgiveness of sins." If the priest were to shorten
or change the form of the consecration of the Body and the Blood, so that
in the change of wording the words did not mean the same thing, he would
not confect the Sacrament. If, truly, he were to add or take away
anything which did not change the meaning, the Sacrament would be valid,
but he would be committing a grave sin.

Pope Pius XII

Encyclical Mediator Dei

62. Assuredly it is a wise and most laudable thing to return in
spirit and affection to the sources of the sacred Liturgy. For
research in this field of study, by tracing it back to its
origins, contributes valuable assistance towards a more thorough
and careful investigation of the significance of feast-days, and
of the meaning of the texts and sacred ceremonies employed on
their occasion. But it is neither wise nor laudable to reduce
everything to antiquity by every possible device. Thus, to cite
some instances, one would be straying from the straight path were
he to wish the altar reduced to its primitive table-form; were he
to want black excluded as a color for the liturgical vestments;
were he to forbid the use of sacred images and statues in
churches; were he to order the crucifix so designed that the
Divine Redeemer's Body showed no trace of his cruel sufferings;
lastly were he to disdain and reject polyphonic music or singing
in parts, even where it conforms to regulations issued by the
Holy See.